Can I upgrade to a 6, compatible with Sprint, without contract

Can I purchase a Sprint-compatible iPhone 6 that does not automatically lock me into 2-year contract? I'm a Sprint customer, with a 4G. I want to upgrade to a 6 with 64 GB, but without entering into another 2-year contract. Sprint actually has several plans, notably a 1GB shared data plan, that do not involve contracts, and would be cheaper than the $87.65 I'm currently paying. (I don't use a lot of storage-intensive apps, and have been using 350-500 MB/Mo, so the 1GB should be fine or now.) I would not be eligible for the new plans if I go for another 2-year contract, so I can't outright purchase the phone from Sprint, Apple, etc. for use with Sprint.

I would still rather pay for the phone up-front (and cheaper?) than have larger monthly payments via a lease or purchase via their EasyPay plan.

The new Data Share plans are available if I lease the phone, or use EasyPay, paying a net $740 plus tax, etc. over 24 months, for the phone. That kicks the monthly cost above what I'm now paying. I asked if I could still qualify for this plan if I acquired a Sprint-compatible phone elsewhere (and cheaper), and was told yes. Can I actually find such a phone?